Negative (photography)
Photographs in which the tones or colors are reversed from their appearance in nature, usually on a transparent support of celluloid, acetate, or on paper, intended for the purpose of producing positive prints
In photography, a negative is an image, usually on a strip or sheet of transparent plastic film, in which the lightest areas of the photographed subject appear darkest and the darkest areas appear lightest. This reversed order occurs because the extremely light-sensitive chemicals a camera film must use to capture an image quickly enough for ordinary picture-taking are darkened, rather than bleach... Wikipedia